198 BOTANICAL GAZETTE [SEPTEMBER 
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33. SCHAFFNER, JoHN H., The fe daciioe Bvisinn in the 2 of 
Agave virginica. Ren GAZETTE 47: 190-214. pls. 12-14. 9. 
34. Stevens, N. M., Studies in spermatogenesis, with special Bes to the 
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w 
an 
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38. YAMANOUCHI, SHIGEO, Sporomeesis i in S ceecoatew. Bor. GAZETTE 45:1- 
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EXPLANATION OF PLATES XII-XIV 
The figures were drawn with the - of a Bausch & Lomb camera anda Zeiss 
apochromatic objective 2™™, an. 2. particular care being taken to ere 
the chromosomes accurately. The ‘etic in plate XII were drawn W! ye 
Zeiss compensating ocular 12, those of plates XIII and XIV with ocular 18. : 
are reduced one-fourth in reproduction, which leaves the figures in plates ae 
and XIV magnified as in my last paper (11) on reduction. 
PLATE XII 
All figures from the plant having 20 chromosomes. cells 
Fic. 1.—Early telophase of the heterotypic mitosis in the pollen mother t: 
before formation of the nuclear membrane; 10 chromosomes, all ae bivalen 
in many the halves are dumb-bell sha at 
Fic. 2.—Same stage; 11 chromosomes, many irregular; 9 chromosomes 
the opposite end of this spindle; dark staining bodies in saicbeed of cytoplas™- 
Fic. 3.—Telophase, showing 10 chromosomes of various shapes. pe 
a 4.—Telophase, showing 10 chromosomes, most of them clearly bivalen 
eicsne f their 
is. 6.—Telophase, downs rr chromosomes, with no indication © Bs 
bivalent character; 9 at opposite end of spindle; apparent size of chrom 
in all figures varies to a certain extent according to the depth of stain. pee 
Fics. 7, 8.—Later telophases, soon after formation of nuclear membrane, 
showing 10 chromosomes. ddle 
FIGs. 9, 10.—Metaphase groups of chromosomes in somatic cells from ™! 
layers of anther wall, each showing 20 chromosomes; indications of a” asi 
ment of the chromosomes in pairs. 
